版权声明:https://blog.csdn.net/qq_37618797 https://blog.csdn.net/qq_37618797/article/details/82903914
需求:
在网页上有一个方块,我们需要键盘上下左右键控制方块的移动。
代码:
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>移动方块</title>
</head>
<body>
<script type="text/javascript">
/* 创建一个div */
var div = document.createElement("div");
/* 将div添加到网页中 */
document.body.appendChild(div);
/* 设置div的样式 */
div.style.width = "100px";
div.style.height = "100px";
div.style.backgroundColor = "red";
div.style.position = "absolute";
div.style.top = "0";
div.style.left = "0";
/* 键盘按下事件 */
document.onkeydown = function(e) {
/* 方块移动的速度,即每按一次方块移动的像素,值越大移动速度越快 */
var speed = 10;
switch(e.which){
// 上
case 38:
div.style.top = parseInt(div.style.top) - speed + "px";
break;
// 下
case 40:
div.style.top = parseInt(div.style.top) + speed + "px";
break;
// 左
case 37:
div.style.left = parseInt(div.style.left) - speed + "px";
break;
// 右
case 39:
div.style.left = parseInt(div.style.left) + speed + "px";
break;
}
}
</script>
</body>
</html>